The oscillatory seismic motion and the daily motion of the Earth in Francesco Travagini's Physica Disquisitio (1669)

Francesco Travagini, chemist, physician and naturalist, well known in Europe in his time, wrote the Physica Disquisitio after directly observing the effects of the 1667 Dubrovnik earthquake on the waters and buildings of Venice, distant by about 800 km. He posed the problem of the origin of the oscillatory motion of earthquakes, an aspect that had never been investigated before. Travagini reported his own observations, aware of being able to formulate only hypotheses, as he could not demonstrate, in a "mathematical and geometrical fashion", how the vertical motion, which was observed in the area of major effects, could be transformed into an oscillatory motion. He made the assumption that the oscillations derived from the daily motion of the Earth, and used an example similar to the one that had been proposed by Galileo to explain the tides, (although without quoting him). Travagini was the first to observe the effect of surface waves at various distances from the epicenter of an earthquake.